Key fobs may be used to gain access into a motor vehicle. Key fobs and motor vehicles may generate credentials created algorithmically based on a key and a salt. The key, the salt, and the credentials are numeric codes, wherein the salt is random data that is used as an input to a one-way function that hashes a password or passphrase. The key fob may be commanded by a user to transmit a credential to the motor vehicle. If the motor vehicle determines that the credential transmitted by the key fob matches a credential stored by the vehicle, the vehicle unlocks or locks the doors or starts the engine. If the credentials stored by the key fob become out of synchronization with the credentials stored by the vehicle, the credential transmitted by the key fob will not match a credential stored in the vehicle, and the vehicle will not act on the command transmitted by the key fob. Motor vehicle dealerships have proprietary control of the relationship and the synchronization between the key fob and the vehicle and their abilities to generate credentials using the key and the salt. If the key fob loses synchronization with the vehicle, the user may need to take the vehicle and the key fob to the dealer during business hours and pay a substantial fee to have the key fob re-synchronized to the vehicle.